logic competition

The 7400 Logic Competition has drawn to a close. The winners were announced and there are quite a few of them. There were fifteen first place winners named, nine second place, and nineteen third place projects. The bounty of quality entries is a testament to the popularity of the contest. It helps to have a wide range of prizes and the post linked above lists all of the sponsors who donated goodies as an incentive.

The board seen above was awarded the reader’s choice, to which the grand prize was awarded. It is a 7400 series calculator. [Umair Mukati] and [Naveed Ahmed] — both are students at the Institute of Industrial Electronics Engineering in Karachi, Pakistan — developed the device as part of a class project. It is capable of adding or subtracting two digit numbers. This includes support for negative numbers as results. We’ve embedded a video demo of the calculator in action after the break.

[Bertho] might have outdone himself this time. He built a Lights Out clone for the 7400 logic competition.

Lights Out is an electronic toy sold by Tiger in the mid 90s. The goal of the game is to turn a 5 by 5 grid of light up buttons off. There’s a catch, though – pressing a button toggles the state of the four surrounding buttons. Check out this Flash game that’s faithful to the original.

[Bertho] read a few Lights Out fan pages and set out to design the circuit. Most of the build is made up of shift registers: the ‘game state’ is saved in five 74hc164 shift registers and a 4557 programmable register. The board is set with a random number generator that toggles bits in the game register until a solvable puzzle is found. A truly spectacular build.

For the light-up buttons themselves, [Bertho] found an old Hack A Day post that describes putting tact switches underneath a LED. The project was put into a nice Plexiglas enclosure after 15 hours of soldering. [Bertho] was kind enough to put a video up of the game in action. Check it out after the break.